This invention generally relates to vacuum excavation methods, and more particularly to devices which may be utilized for clearing rocks and other objects from the generally vertical excavation formed in the vacuum excavation process.
Air vacuum excavation, which is also known as potholing, is an excavation methodology which is utilized to expose utilities to ascertain the exact depth and location of the utilities, typically in preparation for more extensive excavation done in the process of construction activities. Because it is intended to cause a relatively small amount of disruption, air vacuum excavation generally utilizes a small diameter excavation to accomplish this purpose. The larger pieces of equipment utilized for the excavation, such as the vacuum truck, air compressor, etc., may be generally located to the side of the excavation, thereby allowing the survey to take place without major disruptions in surface operations occurring at the site, which is most commonly vehicle traffic along a roadway. Precisely locating underground utilities help the designers to plan construction projects to eliminate potential damage to the utilities and avoiding unnecessary relocations. Air vacuum excavation uses a combination of high-pressure air and a powerful vacuum to safely remove the soil above and around the utility eliminating the risk of damaging the utility which might otherwise occur utilizing traditional methods of mechanical excavation. After the pothole is completed and the utility data is collected then the excavation is backfilled.
So long as the material removed from the excavation during the potholing process is soil, the vacuum excavation process works very well. Because the material being removed is usually backfill, it would be expected that the material being removed would be compacted soil. However, it is not unknown for excavations to be filled with other materials, such as rocks, asphalt and concrete chunks, and other objects and materials.
If larger objects are encountered during the potholing process, major problems can arise. For example, if a large rock is encountered during the excavation, it is necessary to either remove the rock, or to change the location of the pothole. Under the known methods, the rock is typically eliminated by enlarging the excavation with a backhoe or other mechanical excavation machinery and either breaking up the rock with a jack hammer or chisel, or removing the rock. However, utilizing these methods eliminates the primary advantages of potholing, including that it is generally non-destructive and relatively inexpensive.
It is to be appreciated that the present invention may have utility in excavations created by methods other than vacuum excavation and used for purposes other than ascertaining the location of utilities. For example, drilled shafts (also called caissons, drilled piers or pile borings) may be used for bridges and structures where large loads and lateral resistance are major factors. There are a variety of tools utilized by construction contractors when constructing these types of excavations. However, regardless of the type of equipment used, hard rock and individual rock bodies and fragments are often encountered and often the excavation tool cannot advance until the rock is removed. Removal of the rock bodies and fragments can be a laborious and time consuming task to accomplish, particularly if specialized and/or expensive equipment is required to be brought on site for removal. In addition, the utilization of this equipment may require shutting down normal activities for mobilization and operation of the equipment, such as limiting or closing down traffic on a roadway. Accordingly, a need exists for a device which is capable of removing objects from a generally vertical excavation where the device is readily available, relatively compact, and relatively inexpensive.